fix CircleMarker documentation
fix CircleMarker documentation

refs #6663

SudiptaBiswas/moose,idaholab/moose,friedmud/moose,jasondhales/moose,bwspenc/moose,lindsayad/moose,milljm/moose,permcody/moose,jessecarterMOOSE/moose,laagesen/moose,jasondhales/moose,dschwen/moose,stimpsonsg/moose,SudiptaBiswas/moose,sapitts/moose,milljm/moose,laagesen/moose,SudiptaBiswas/moose,milljm/moose,backmari/moose,jessecarterMOOSE/moose,jasondhales/moose,permcody/moose,nuclear-wizard/moose,jhbradley/moose,Chuban/moose,katyhuff/moose,liuwenf/moose,katyhuff/moose,jessecarterMOOSE/moose,jasondhales/moose,harterj/moose,bwspenc/moose,laagesen/moose,backmari/moose,yipenggao/moose,andrsd/moose,harterj/moose,bwspenc/moose,YaqiWang/moose,laagesen/moose,sapitts/moose,yipenggao/moose,jhbradley/moose,harterj/moose,stimpsonsg/moose,yipenggao/moose,katyhuff/moose,nuclear-wizard/moose,SudiptaBiswas/moose,idaholab/moose,katyhuff/moose,joshua-cogliati-inl/moose,milljm/moose,liuwenf/moose,Chuban/moose,Chuban/moose,joshua-cogliati-inl/moose,bwspenc/moose,YaqiWang/moose,jessecarterMOOSE/moose,sapitts/moose,friedmud/moose,yipenggao/moose,jhbradley/moose,dschwen/moose,milljm/moose,lindsayad/moose,idaholab/moose,friedmud/moose,permcody/moose,joshua-cogliati-inl/moose,joshua-cogliati-inl/moose,jessecarterMOOSE/moose,permcody/moose,stimpsonsg/moose,sapitts/moose,lindsayad/moose,andrsd/moose,harterj/moose,stimpsonsg/moose,idaholab/moose,Chuban/moose,andrsd/moose,bwspenc/moose,lindsayad/moose,nuclear-wizard/moose,liuwenf/moose,dschwen/moose,jhbradley/moose,YaqiWang/moose,backmari/moose,sapitts/moose,liuwenf/moose,dschwen/moose,SudiptaBiswas/moose,lindsayad/moose,nuclear-wizard/moose,andrsd/moose,friedmud/moose,harterj/moose,andrsd/moose,idaholab/moose,laagesen/moose,liuwenf/moose,liuwenf/moose,backmari/moose,dschwen/moose,YaqiWang/moose